THE EFFECTS OF DIMETHYLSULFIDE UPON MARINE AEROSOL CONCENTRATIONS

A simplified dimethylsulfide (DMS) oxidation mechanism is used in a box model to predict the vapor source rates of the major sulfur-containing products, methanesulfonic acid and sulfuric acid, in the marine boundary layer. These vapor source rates drive an integral aerosol model that predicts gas-to-particle conversion of the acid species in the presence of water vapor. The effects of latitudinal variations in background hydroxyl radical concentrations, temperatures, and relative humidities upon the predicted aerosol number concentrations are presented, and the sensitivity of the predictions to uncertainties in aerosol model input parameters is discussed. The predictions support a dependence of marine aerosol concentrations on latitude, as noted in some observations. Realistic choices of aerosol model parameters yield number concentrations that are consistent with observed concentrations in remote marine areas.